Count documentation

[Articoking]

• Closes Documentation of Dataset.count() is ambiguous #8055
• User visible changes (including notable bug fixes) are documented in whats-new.rst

I've changed the example to include a 0 value which clearly shows that only NA values are ignored in the count. I've only modified the "see also" section for count since as mentioned in #8055 it is a bit of an outlier among the aggregation methods. I believe that this is not a long term fix since the single line summary of the method is of little use, but at least with this no one will have to take a look at the source code to quickly get what count does.

Feel free to correct any problems or suggest any changes, as I am quite new to contributing to projects like this and have little idea of what I'm doing 😅

[welcome]

Thank you for opening this pull request! It may take us a few days to respond here, so thank you for being patient.
If you have questions, some answers may be found in our contributing guidelines.

[dcherian]

Feel free to correct any problems or suggest any changes, as I am quite new to contributing to projects like this and have little idea of what I'm doing

Looks like you did really well. Thanks!

I believe that this is not a long term fix since the single line summary of the method is of little use, but at least with this no one will have to take a look at the source code to quickly get what count does.

Are you interested in adding a description field to Method? We can also just get to it later :)

[headtr1ck]

Thanks for the PR!
You can add an entry in whats-new:)

I guess long term we should clean up the generation script a bit and remove all the special casings with dicts (or default dicts). But that's another PR.

[Articoking]

Are you interested in adding a description field to Method? We can also just get to it later :)

I would be glad to do so if I find the time in the next few days! Should such a field be used only for count or should I try to write a custom signature for each method?

[dcherian]

Should such a field be used only for count or should I try to write a custom signature for each method?

#7378 suggests that most, if not all, methods would benefit from an extra line or two.

I'll merge this one since it's a pretty good upgrade already. Thanks!

[welcome]

Congratulations on completing your first pull request! Welcome to Xarray! We are proud of you, and hope to see you again!